WARNING in sta_info_insert_rcu

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    eff48dde Merge tag 'trace-v5.9-rc5' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b4e8e3900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5f4c828c9e3cef97
dashboard link: https://syzkaller.appspot.com/bug?extid=ef4ca92d9d6f5ba2f880
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=167e5707900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1765b19b900000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10341dab900000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12341dab900000
console output: https://syzkaller.appspot.com/x/log.txt?x=14341dab900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ef4ca92d9d6f5ba2f880@xxxxxxxxxxxxxxxxxxxxxxxxx

wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
------------[ cut here ]------------
WARNING: CPU: 0 PID: 72 at net/mac80211/sta_info.c:529 sta_info_insert_check net/mac80211/sta_info.c:529 [inline]
WARNING: CPU: 0 PID: 72 at net/mac80211/sta_info.c:529 sta_info_insert_rcu+0x27a/0x2ba0 net/mac80211/sta_info.c:707
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 72 Comm: kworker/u4:3 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: phy4 ieee80211_iface_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 panic+0x382/0x7fb kernel/panic.c:231
 __warn.cold+0x20/0x4b kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:sta_info_insert_check net/mac80211/sta_info.c:529 [inline]
RIP: 0010:sta_info_insert_rcu+0x27a/0x2ba0 net/mac80211/sta_info.c:707
Code: 24 e8 3a 79 b8 f9 0f b6 85 50 ff ff ff 31 ff 83 e0 01 41 89 c7 89 c6 e8 44 75 b8 f9 45 84 ff 0f 84 c5 00 00 00 e8 16 79 b8 f9 <0f> 0b 41 bd ea ff ff ff e8 09 79 b8 f9 48 8b bd 30 ff ff ff e8 ed
RSP: 0018:ffffc90001017958 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888093338c00 RCX: ffffffff87bdc51c
RDX: ffff8880a9394040 RSI: ffffffff87bdc52a RDI: 0000000000000001
RBP: ffffc90001017aa0 R08: 0000000000000000 R09: ffff88809333925f
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000500177e9
R13: ffff8880a8916048 R14: ffff8880a8916000 R15: 0000000000000001
 ieee80211_ibss_finish_sta+0x212/0x390 net/mac80211/ibss.c:592
 ieee80211_ibss_work+0x2c7/0xe80 net/mac80211/ibss.c:1699
 ieee80211_iface_work+0x7d2/0x8f0 net/mac80211/iface.c:1438
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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https://goo.gl/tpsmEJ#testing-patches